Electrically adjustable semiactive damper control

Abstract

One or several vibration dampers of a vehicle suspension have a damping force arrangement wherein a control signal is computed within the actuating range in accordance with a standard control method for adjusting the damper characteristic. The drive of a damper adjustable in accordance with this invention is so improved that body movements (notwithstanding a harder adjusted damping for critical driving situations) are substantially suppressed as early as possible. In specific driving situations, the adjusting range of the damper force is changed in that the upper limit of the adjusting range is raised or lowered and/or the lower limit of the adjusting range is raised or lowered. A soft damper setting takes place preferably in dependence upon signals which announce or display a change of the vehicle longitudinal deceleration or vehicle transverse acceleration.

What is claimed is:  
     
         1 . A method for controlling the damping force for at least one vibration damper of a vehicle wheel suspension of a vehicle, the method comprising the steps of: 
 providing a damper for generating a damper force and said damper having a damper characteristic adjustable within an adjusting range for the damping force delimited by upper and lower limit values;    detecting a first signal representing the vertical velocity at a part of said vehicle chassis as a suspended mass;    detecting a second signal representing the vertical velocity of the unsuspended wheel mass;    computing an input control signal based on said first and second signals for adjusting said damper characteristic within said adjusting range in accordance with a standard control process;    discretely or continuously adjusting said damping characteristic to said input control signal; and,    changing said adjusting range in specific driving situations so as to cause one or both of said upper and lower limits to be raised or lowered.    
     
     
         2 . The method of  claim 1 , comprising the further step of limiting a damper soft setting in dependence on signals which indicate a change of vehicle longitudinal deceleration.  
     
     
         3 . The method of  claim 1 , comprising the further step of limiting a damper soft setting in dependence upon signals which indicate a change of the vehicle transverse acceleration.  
     
     
         4 . The method of  claim 1 , comprising the further step of limiting a damper hard setting when detecting large roadway unevenness utilizing adaptive algorithmic circuits or self-learning units.  
     
     
         5 . The method of  claim 1 , said vehicle having a vehicle body and said method comprising the further step of permitting a damper hard adjustment in dependence upon the body velocity so as to cause a widening of the adjusting range in the direction of a damper hardening and so as to cause a narrowing of the adjusting range in the direction of a damper hardening.  
     
     
         6 . The method of  claim 1 , comprising the further step of narrowing said adjustment range in a direction of a damper hardening with a permanent priority relative to limiting in the direction of a damper soft setting.  
     
     
         7 . The method of  claim 1 , comprising the further step of limiting an actuating variable in a direction of a soft damper adjustment when determining a defect in the control algorithm.  
     
     
         8 . The method of  claim 1 , comprising the further step of adapting the adjusting range to a specific driving situation.  
     
     
         9 . The method of  claim 8 , wherein the adaptation of said adjusting range always takes p lac e when said specific driving situation is announced .  
     
     
         10 . The method of  claim 1 , wherein said standard control process is the skyhook process.  
     
     
         11 . An arrangement for controlling the damping force for at least one vibration damper of a vehicle wheel suspension of a vehicle, the arrangement comprising: 
 a damper for generating a damper force and said damper having a damper characteristic adjustable within an adjusting range for the damping force delimited by upper and lower limit values;    means for detecting a first signal representing the vertical velocity at a part of said vehicle chassis as a suspended mass;    means for detecting a second signal representing the vertical velocity of the unsuspended wheel mass;    means for computing an input control signal based on said first and second signals for adjusting said damper characteristic within said adjusting range in accordance with a standard control method;    a damping force unit for discretely or continuously adjusting said damping characteristic to said input control signal; and,    means for changing said adjusting range in specific driving situations so as to cause one or both of said upper and lower limits to be raised or lowered.    
     
     
         12 . The arrangement of  claim 11 , further comprising means for limiting a damper soft setting in dependence on signals which indicate a change of vehicle longitudinal deceleration.  
     
     
         13 . The arrangement of  claim 11 , further comprising means for limiting a damper soft setting in dependence upon signals which indicate a change of the vehicle transverse acceleration.  
     
     
         14 . The arrangement of  claim 11 , further comprising means for limiting a damper hard setting when detecting large roadway unevenness utilizing adaptive algorithmic circuits or self-learning units.  
     
     
         15 . The arrangement of  claim 11 , said vehicle having a vehicle body and said arrangement further comprising means for making a hard damper setting in dependence upon the body velocity so as to cause a widening of the adjusting range in the direction of a damper hardening and so as to cause a narrowing of the adjusting range in the direction of a damper hardening.  
     
     
         16 . The arrangement of  claim 11 , further comprising means for narrowing said adjustment range in a direction of a damper hardening with a permanent priority relative to limiting in the direction of a damper soft setting.  
     
     
         17 . The arrangement of  claim 11 , further comprising means for limiting an actuating variable in a direction of a soft damper adjustment when determining a defect in the control algorithm.  
     
     
         18 . The arrangement of  claim 11 , further comprising means for adapting the adjusting range to a specific driving situation.